Recycled Polyolefin Oligomer Identification for Food Contact Clearance
Clearing recycled polyolefins for food contact demands HPLC-GC-FID and GCxGC-MS identification of oligomeric fractions evaluated against TTC thresholds.
POMH Characterization
Meaning
Analytical profiling identifies the unsaturated hydrocarbon fractions that originate from polyolefin packaging materials during food safety evaluations. Performs POMH characterization to quantify these mono-unsaturated oligomers and distinguish them from mineral oil hydrocarbons that might have migrated from recycled paperboard. This identification is crucial for verifying that the migrating compounds are benign polymer residues rather than toxic mineral oil aromatic hydrocarbons.
Chemical Identification
Unsaturated oligomers are generated as by-products during the polymerization or high-temperature processing of polyethylene and polypropylene. During POMH characterization, analysts target these specific hydrocarbons to map the oligomeric profile of the polymer matrix. These mono-unsaturated compounds share some physical behaviors with saturated oligomers but have different chemical reactivities.
Understanding their presence helps compounders optimize the thermal stability of the raw resin.
Chromatographic Method
Liquid chromatography combined with gas chromatography separates these oligomers from other hydrocarbon fractions. The analytical separation isolates the mono-unsaturated compounds based on their chemical structure and molecular weight. On the resulting chromatogram, these polymer-derived substances appear in specific elution windows that overlap with mineral oil fractions.
Detailed profiling resolves these overlapping peaks, preventing false allegations of packaging contamination. This testing is crucial for high-purity applications like medical devices and infant food packaging.
Process Control
Moulding parameter adjustments can minimize the formation of these oligomeric by-products during manufacturing. Reducing the melt temperature and minimizing the residence time in the injection barrel lowers thermal degradation. This proactive process control ensures that finished parts remain compliant with strict migration thresholds.